1. Field of the Invention
The present invention relates to a variable venturi carburetor for an internal combustion engine (hereinafter referred to as "engine") in which constant negative pressure in a venturi portion is utilized for controlling its air-fuel ratio.
2. Description of the Prior Art
In a conventional variable venturi carburetor, a fuel bypass provided in a float chamber detours a main fuel metering portion to communicate with a downstream portion of a throttle valve. Therefore, the flow of fuel flowing in the fuel bypass is widely changed in proportion to change in engine load such that the air-fuel ratio cannot be maintained constant with respect to the change in engine load.